140.960-IOM (JUN 2016)
Page 44
IDCF & IDC3 EVAPORATIVE CONDENSERS
MAINTENANCE
FAN DRIVE SYSTEM
System Descriptions
• Direct Drive Motor (0406 & 0412): Factory mounted direct
drive system with premium efficiency totally enclosed
motors.
• Externally Mounted Motor (0709 & 0718): A belt drive
system with a premium efficiency totally enclosed motor
mounted outside the airstream is provided on these units.
• Internally Mounted Motor (1012-2440): A belt drive system
with a premium efficiency totally enclosed motor mounted
inside the airstream is provided on these units.
Inspection and Maintenance
•
Direct Drive System:
Periodically check the rotation of the
fan and motor assembly. No adjustments are necessary.
•
Fortitude Power Train:
These drives require a periodic
check of the belt condition and, when necessary, tension
adjustment. The recommended service intervals are as
follows:
1. Initial Start-up:
• Internally mounted motor: The drive has been
tensioned and aligned at the factory, however, prior
to initial startup, check belt tension (1012 - 2440).
• Externally mounted motor: The motor base assembly
has been pre-aligned at the factory. Mount the motor
base assembly to the unit and verify alignment. Install
the belt and follow the belt tensioning directions
(0709 & 0718).
2. Seasonal Start-up: Readjust the belt tension.
3. Operation: After the first 24 hours of operation, readjust
the belt tension on a new unit start-up or installation
of a new belt. Thereafter, check the belt condition
monthly, and adjust tension as necessary. Readjust
tension at least once every three (3) months.
Fan Belt Adjustment
To properly adjust the belt tension, position the fan motor so that
moderate pressure on the belt midway between the sheaves will
produce the deflection shown in Figures 15a and 15b.
• Belt tension check:
1. Place a straight edge along the belt from sheave to
sheave as shown in Figure 15a, or use a tape measure
as shown in Figure 15b, to measure belt deflection.
2. Apply a moderate force by hand (approximately 40
lb/18.1 kg) evenly across the width of the belt in the
center of the span between the sheaves.
3. There is adequate belt tension if the belt deflects
between 1/4” and 3/8” as shown in Figures 15a and 15b.
• Belt tension adjustment (if required):
1. Remove the locking wrench (wrench attached to casing
near motor/door) by loosening the plastic thumbscrew.
2. Using the supplied locking wrench, wrench, or impact
gun, turn the motor base adjusting screw (Figures 4a and
4b) clockwise to tension the belt or counterclockwise
to relieve belt tension. During adjustment of the belt
tension, rotate the drives several times by hand to
evenly distribute the tension throughout the belt.
3. When the belt is properly tensioned, align the adjustment
bolt to facilitate replacement of the locking wrench.
Replace the locking wrench and tighten the plastic
thumbscrew to secure.
NOTICE
If belts are tensioned properly, there should be no “chirp”
or “squeal” when the fan motor is started.
Figure 58a: Checking Belt Tension
Figure 58b: Checking Belt Tension
Drive Alignment Check And Adjustment
1. Place a straight edge across the driver and the driven
sheaves as shown in Figure 16.
2. The straight edge should contact all four points as
shown in Figure 16, indicating proper drive alignment.
3. There should be no more than 1/16” deviation from four
points of contact.
4. In case of realignment, loosen the motor sheave and
align it with the fan sheave. Allow 1/4” for draw-up as
the bushing screws are retightened.
• Check the drive alignment annually to ensure maximum
belt life.
Figure 59 - Standard Drive Alignment
